The TH-57 aircraft is the military version of the commercial Model 206 Jet Ranger helicopter manufactured by Bell Helicopter Textron, Inc. The aircraft is powered by one Allison Gas Turbine 250-C20J turbo shaft engine down rated to 317 shaft horsepower. The primary mission of TH-57 is to train student naval aviators in the fundamentals of helicopter flight for their transition to operational fleet aircraft in the U. S. Navy, U. S. Marine Corps, and selected international armed forces.